Percutaneous vascular procedures form an integral portion of radiological and cardiological medical practices. It is estimated that approximately one million invasive procedures are performed each year, including peripheral and carotid angiograms, catheterizations, angioplasties, and atherectomies. In such procedures, a puncture opening distending sheath assembly is introduced into a blood vessel, for example, the femoral artery in a patient's leg. A medical device, such as a catheter, is introduced through the sheath assembly and then advanced through the blood vessel to the coronary, or other operative, region.
The majority of these invasive procedures are performed using the Seldinger technique to gain percutaneous vascular access to the blood vessel. According to this technique, the blood vessel, which in the case of the femoral artery is typically located one half inch or more beneath the skin, is punctured through the overlying tissue by a hollow-core needle. A guide wire then is threaded through the hollow core of the needle and into the artery. The needle is subsequently withdrawn from the artery, while the guide wire is maintained in place. Next, a blood vessel wall dilator and a thin-walled, tubular, puncture-distending sheath are introduced into the artery with the blood vessel dilator inside the sheath. The dilator and the sheath are moved along the guide wire and through the puncture site to an intravascular position. The dilator extends outwardly of the end of the sheath and gradually distends the puncture opening as it is advanced into the blood vessel wall until the opening will receive the sheath. The guide wire and the dilator are then withdrawn from the artery while the distending sheath assembly is left in place. Prior to the introduction of medical devices into the artery, anti-coagulants are administered to prevent blood clotting. Finally, a catheter, or other medical device, may be inserted through the sheath assembly to perform the necessary invasive procedure.
Following the medical procedure, the medical device is removed from the sheath assembly and the sheath assembly is removed from the puncture site in the artery. The time which elapses prior to sheath removal varies considerably depending on the procedure being performed. Other factors which govern the amount of lapsed time prior to sheath removal include the size of the sheath employed, the amount of anti-coagulant administered, and the patient's clinical circumstance. The combinations of all of these factors often results in a relatively long waiting period between the completion of the procedure and the removal of the sheath assembly, which adds to patient discomfort and anxiety.
Once the sheath assembly is removed from the artery, it has been customary to obtain hemostasis at the puncture site by applying indirect, external pressure to the femoral artery and vein. This is usually accomplished manually by a nurse or physician, or with the aid of a mechanical clamp, employed by the nurse or physician. Often, compression must be applied for ten to thirty minutes before sufficient clotting occurs. Once hemostasis is achieved, a pressure dressing is typically applied to the patient's leg for several hours. In addition, six to twelve hours of bed rest is typically required to reduce the risk and incidence of hematoma formation.
Although manual compression has proven successful in obtaining hemostasis over the years, there are numerous problems and disadvantages associated with this method. The procedure is extremely time-consuming from both a patient and a physician standpoint and further is an inefficient use of the medical professional staff. Moreover, manual and mechanical compression are extremely uncomfortable to the patient and frequently is associated with vaso-vagal episodes. In addition, bruise or hematoma formation at the entry site often occurs as a result of internal bleeding of the punctured artery before clotting blocks the puncture. The possibility of psuedoaneurysm formation also exists with the manual compression technique of achieving hemostasis.
In response to some of the problems associated with manual compression, a percutaneous apparatus and method for forming a vascular seal has been developed and commercially exploited under the trade name VASOSEAL by Datascope Corporation of Montvale, N.J. According to this method, a measuring device is used to calculate the distance between the skin surface and the operative vessel wall at the beginning of the catheterization procedure. Then, when the invasive procedure is completed and the medical device and distending sheath assembly have been withdrawn, an applicator is inserted through the patient's skin and overlying tissue down the passageway formerly receiving the sheath assembly to the previously measured depth. The applicator is actuated to deliver a volume of collagen to the puncture site. The collagen utilized by the Datascope apparatus and method is made of resorbable natural fibers and attracts and activates platelets to form a coagulum at the vessel surface, sealing the surface of the artery. Such a collagen seal is typically formed in less than five minutes, involving significantly less time and labor than that required by the manual compression technique. The collagen itself applies a discrete pressure against the blood vessel wall, much like finger pressure delivered to a skin wound, but some direct, external pressure still must be applied to the entry site once the collagen has been injected.
Although the Datascope method significantly reduces the amount of manual compression required, the necessary manual compression remains an inefficient use of a physician's time. Moreover, the Datascope method involves some risk associated with deploying collagen intravascularly, or only at an approximate location along the vessel wall, rather than at a specific, identifiable position on the vessel wall surface. For example, manipulation of the blood vessel during the catheterization procedure may cause the blood vessel to shift, reducing the accuracy of the measurement taken before the catheterization procedure. Intravascular deposition of collagen can produce an embolism and possible ischemia within the patient's leg, which may require further medical intervention. Deposits of collagen remote of the puncture site may be ineffective in establishing hemostasis.
Another method for closing and sealing an artery following removal of a catheter is disclosed in U.S. Pat. No. 4,929,246 to Sinofsky. This method involves applying laser energy to a puncture site to thermally weld the artery. In a preferred embodiment, a sheath assembly is withdrawn to a spaced distance from the artery and puncture site and a tube having a balloon at its distal end is advanced through the sheath assembly. The balloon is then inflated to apply pressure to the exterior wall of the artery, temporarily blocking blood flow from the puncture. The tube also carries an optical fiber which extends into the balloon and directs a beam of laser energy against the interior of the balloon. The laser energy indirectly thermally welds the artery wall. Creating a vascular seal with a laser as disclosed in the Sinofsky patent, however, is a costly, somewhat indirect and a complex solution to hemostasis.
It also is widely known in the medical field to heat weld exposed blood vessels during an operative procedure or to electrosurgically coagulate escaping blood to effect vascular sealing. For example, laser energy has been routinely directly employed to provide the necessary thermal energy to weld brachial arteries during a Sones procedure. In addition, both electro-cautery and electro-coagulation have been used to seal exposed small blood vessels under direct observation during operative procedures. It is believed that such electrosurgical procedures have not previously been employed to effect rapid percutaneous vascular sealing of unseen blood vessels following an invasive medical procedure.
The difficulties suggested in the preceding are not intended to be exhaustive but rather are among many which tend to reduce the effectiveness of and physician satisfaction with prior percutaneous vascular sealing devices. Other noteworthy problems may also exist; however, those presented above should be sufficient to demonstrate that such vascular sealing apparatus and methods appearing in the past will admit to worthwhile improvement.
Accordingly, it is therefore a general object of the invention to provide percutaneous vascular sealing apparatus and method which will obviate or minimize difficulties of the type previously described.
It is a specific object of the invention to provide a percutaneous vascular sealing apparatus and method which rapidly creates a vascular seal at a puncture site in a blood vessel wall following an invasive medical procedure.
It is another object of the invention to provide a percutaneous vascular sealing apparatus and method which enables accurate identification of an external surface of an operative blood vessel, thereby preventing accidental actuation of the sealing apparatus at an intravascular location or an ineffective remote location.
It is still another object of the invention to provide a percutaneous vascular sealing apparatus and method which reduces the amount of medical staff care necessary to achieve hemostasis following an invasive medical procedure, allows a patient to be ambulatory soon after the procedure, and, thereby, reduces the length of the hospital stay.
It is a further object of the invention to provide a percutaneous vascular sealing apparatus and method which eliminates the need for mechanical clamps to effect hemostasis and reduces the time required for pressure dressings upon completion of an invasive medical procedure.
It is yet a further object of the invention to provide a percutaneous vascular sealing apparatus and method which reduces the risk of rebleeding, hematoma formation, and psuedoaneurysms formation following an invasive medical procedure.
It is still a further object of the invention to provide a percutaneous vascular sealing apparatus and method which reduces patient pain and discomfort associated with invasive medical procedures.
It is yet another object of the invention to provide a percutaneous vascular sealing apparatus and method which is relatively inexpensive to manufacture and use, is disposable, and, thus, is practical for everyday use.